Section 2 Assessment for LMA notation

2.1.1 The LMA notation provides a means for demonstrating that a ship’s manoeuvring performance complies with the minimum standards set by the IMO in Resolution MSC.137(76) - Standards for Ship Manoeuvrability - (adopted on 4 December 2002).

2.2.1 It is recommended that a ship’s manoeuvring performance be assessed at the design stage through calculation and/or model tests in order to determine an early estimation of manoeuvring performance.

2.2.2 The means of assessment (detailed computations, simulations and/or model tests) are to be proposed by the designer in agreement with the Owner and LR. These are to be undertaken in accordance with an appropriate standard for the manoeuvring abilities defined in Vol 3, Pt 1, Ch 4, 2.3 Manoeuvres to be assessed and the results submitted to LR for information. Where an alternative standard or method is proposed this is to be submitted to LR for consideration.

2.2.3 Any model tests are to be carried out by a recognised facility that is acceptable to LR and a report is to be submitted detailing the test arrangements, schedule of tests, and results, presented in both diagrammatic and tabular form.

2.2.4 LR may, when requested, undertake calculations on behalf of designers and make recommendations with regard to suitability of any required model tests.

2.2.5 Final verification of the assignment of the LMA notation will be dependent on the results of sea trials, see Vol 3, Pt 1, Ch 4, 4 Verification trials.

2.3.1 The assessments are to give estimates of the primary manoeuvring indices from the following:

1. Ship's turning circles to port and starboard with maximum design rudder angle starting from:

   • The approach speed, see Vol 3, Pt 1, Ch 4, 4.4 Approach conditions 4.4.1, coupled with a pull-out manoeuvre.
   • Full sea speed and constant engine(s) control setting.
   • Half manoeuvring ship speed and constant engine(s) control setting.

2. Ship's stopping manoeuvring characteristics by the application of astern power, from:

   • The approach speed, see Vol 3, Pt 1, Ch 4, 4.4 Approach conditions 4.4.1.
   • Full sea speed.
   • Full manoeuvring speed ahead.
   • Half manoeuvring speed ahead.
   • Slow manoeuvring speed.

3. Ship’s yaw (rate of change of heading) checking characteristics through the 20º/20º and 10º/10º zig-zag manoeuvres, from the approach speed, see Vol 3, Pt 1, Ch 4, 4.4 Approach conditions 4.4.1, with constant engine(s) control setting.

4. Ship’s initial turning ability at the approach speed, see Vol 3, Pt 1, Ch 4, 4.4 Approach conditions 4.4.1.

5. Where these manoeuvres indicate dynamic instability, additional representative manoeuvres may be required, for example, a spiral manoeuvre, see Vol 3, Pt 1, Ch 4, 4.5 Representative manoeuvres (LMA notation) 4.5.2.

2.3.2 For the purpose of the assessments, thrust breakdown due to cavitation during manoeuvring conditions and the effects of wind, tide, current and shallow water may be ignored.

2.4.1 For the assignment of the LMA notation, the ship is to be assessed in accordance with the requirements of IMO Resolution MSC.137(76) - Standards for Ship Manoeuvrability - (adopted on 4 December 2002).

2.4.2 In cases where a large displacement ship does not satisfy the stopping standard referred to in Vol 3, Pt 1, Ch 4, 2.4 Manoeuvring standards 2.4.1, special consideration will be given to the ship’s stopping capability.

2.5.1 The results of the assessments made in accordance with Vol 3, Pt 1, Ch 4, 2.2 Verification Requirements (stating the assumptions made), together with additional information gained from the verification trials, and trial data for the man overboard manoeuvre, are to be presented in diagrammatic and tabular form and included in a bridge poster and a manoeuvring booklet.

2.5.2 The poster is to be permanently displayed in the bridge, and is to contain a clear warning that the data presented is applicable to calm weather with no wind, waves or current. The booklet is to be placed on board and is to contain comprehensive details of the ship’s manoeuvring characteristics.

2.5.3 The format, data and content of the bridge poster and the manoeuvring booklet are to meet the requirements of IMO Resolution A.601(15) – Provision and Display of Manoeuvring Information on Board Ships – (Adopted on 19 November 1987).

2.6.1 The manoeuvring information card is to contain a summary of the ship’s manoeuvring capabilities and principal particulars and is to be kept on the wheelhouse for the information of the pilot. The format and data to be presented on this card are to satisfy the requirements of IMO Resolution A.601(15) – Provision and Display of Manoeuvring Information on Board Ships – (Adopted on 19 November 1987).